BIOGEOSPHERE
Bilingual Biology and Geology
I.E.S. "J.S.Elcano (Sanlúcar Bda.)
3. Birds
There are about 10,000 species of birds.
Birds appeared 160 million years ago.
They evolved from reptiles related to dinosaurs that developed feathers
and capacity for flying.
a) Habitat
Birds are terrestrial tetrapods, although some of them are adapted to pass
a lot of time on water (e.g. penguin). Most are flying animals but some have
lost this capacity (e.g. ostrich)
b) Morphological characteristics
- They have four limbs. The forelimbs are wings and the hind limbs are legs.
- Their body is divided into: head, trunk and tail.
- Their skin is covered by feathers. They protect the bird of heat loss
and are the sustentation surface for flying.
c) Vital functions:
Nutrition:
The digestive system is complete. They have mouth covered by a beak without teeth, a very muscular stomach, intestine and anus. It opens outside by the cloaca, a common opening to digestive, reproductive and excretal systems. Their feeding is very diverse and the shape of beak is adapted to.
They need a lot of energy for flying so that they have many adaptations to increase the amount of oxygen that arrives to muscles.
Birds breathe through lungs. They have special organs called air sacs attached to their lungs that increase the amount of oxygen that a bird can take.
They have double circulation. Their heart has four chambers (two atriums and two ventricles),
so that they have complete circulation.
They have two kidneys.
Interaction
They have a well developed brain and sense organs:
eyes (with eyelids), ears (without auricles), taste and touch.
They are homeotherms (warm-blooded).
Bird skeleton is compact and strong. They have some fused bones (some of the vertebrae, ribs and hip bones).
This makes the skeleton more rigid than in other vertebrates and allows move wings more efficiently.
They have hollow bones that reduce the weight of bird, making easier fly.
They have keel, a prolongation of the breastbone (sternum) that provides of a good attached for the powerful flight muscles.
Reproduction:
Fertilization is internal.
They are oviparous this is the embryo develops inside an egg.
This egg has a hard and rigid shell and an internal impermeable membrane (amnion).
They incubate the eggs and take care of their young (chicks).
d) Classification:
- Carinatae (flying birds)
They have keel.
It is the most numerous group.
- Ratites (non-flying birds)
They don’t have keel and are adapted to running.
Their wings are atrophied and reduced.
READING ACTIVITIES
After reading the text, copy and answer the following questions into your notebook:
Remember: you must make complete sentences.
3.1. The shape of the beak of Birds is an adaptation to the type of feeding.
Can you relate every picture on the right with its correspondent
way of feeding?
a. They use it to make holes in wood
looking for insects.
b. They use it to break seeds.
c. They use it like a harpoon to fish.
d. They use it to tear meat.
e. They use it to sweep water surface
to catch molluscs and insects.
3.2. Listen and indicate which of these characteristics are adaptations
for flying
Now,
check
your
answers!
LISTENING ACTIVITIES
Download this worksheet
and complete it,
while you listen this audio.
SPEAKING ACTIVITIES
Now, in turns with your partner,
answer the questions in the worksheet.
(Diccionario Ing-Esp)
(Juegos de vocabulario)
(Visual dictionary)
(Visual dictionary)
(Glosario de C. Naturales)
(Science audio-glossary)
(Science audio-glossary)
(Pronunciación)
(Enciclopedia de C. Naturales)
(Tabla periódica)
Eva Mª
López Rodríguez
Departamento
Biología y Geología
IES " J. S. Elcano"
Sanlúcar de Barrameda